Abstract:

A paddle lead includes a plurality of electrodes configured in at least
three rows of three electrodes with the second, intermediate row operable
to provide anode guarding. The paddle lead further includes a plurality
of grooves disposed on a surface opposite the electrodes to facilitate
the insertion of the paddle lead within a patient by inhibiting the
veering of the paddle lead to one side or the other of the dorsal column
as the paddle lead is advanced along the dorsal column midline during
implantation.

Claims:

1. A paddle lead, comprising:a body having a first side and a second
side;at least one electrode disposed on the first side of the body; anda
first groove disposed on the second side of the body, such that when the
paddle lead is being implanted in a patient, at least a portion of the
first groove engages the patient and facilitates the advancement of the
paddle lead towards a targeted implant site in the patient.

2. The paddle lead of claim 1 and further including a second groove
disposed on the second side of the body.

3. The paddle lead of claim 2 wherein the first groove and the second
groove extend generally parallel to each other.

4. The paddle lead of claim 1 wherein when the paddle lead has been
implanted in the patient, at least a portion of the first groove engages
the patient and inhibits the movement of the paddle lead with respect to
the position of the paddle lead in the patient.

5. The paddle lead of claim 1 wherein the first groove is an arcuate
groove.

6. A paddle lead, comprising:a body having a first side and a second side,
first side being generally planar;the first side of the body includes a
plurality of electrodes; anda plurality of grooves disposed on the second
side of the body, such that when the paddle lead is being implanted in a
patient, at least a portion of the plurality of grooves engage the
patient and facilitate the advancement of the paddle lead towards a
target implant site by inhibiting the paddle lead from veering away from
the target implant site.

7. The paddle lead of claim 6 wherein each of the plurality of grooves are
generally parallel to each other.

8. The paddle lead of claim 7 wherein when the paddle lead has been
implanted in the patient, at last a portion of the plurality of grooves
engage the patient and inhibit the movement of the paddle lead with
respect to the position of the paddle lead in the patient.

9. The paddle lead of claim 8 wherein the plurality of electrodes are
arranged in at least a first row, a second row and a third, with each of
the first, second and third rows being generally parallel and extending
from a first edge of the body to a second edge of the body, and each of
the first, second and third rows having at least three contacts, the
second row operable to provide anode guarding for at least one of the
first and third rows.

10. The paddle lead of claim 9 wherein at least one of the plurality of
grooves is an arcuate shaped groove.

11. A paddle lead, comprising:a body having a first side and a second side
and a first edge and a second edge;the first side of the body including
at least a first row of at least three electrodes, a second row of at
least three electrodes and a third row of at least three electrodes;each
of the first, second and third row of electrodes being generally parallel
and extending from the first edge of the body to the second edge of the
body, with the second row being positioned intermediate the first and
third rows; andthe second row of electrodes operable to provide anode
guarding for at least one of the first and third rows of electrodes.

12. The paddle lead of claim 11 wherein each of the electrodes in the
second row are electrically connected together and operate in a common
state.

13. The paddle lead of claim 12 where each of the electrodes in the first
row are operable in an independent state.

14. The paddle lead of claim 13 and further including a plurality of
grooves disposed on the second side of the body, such that when the
paddle lead is being implanted in a patient, at least a portion of the
plurality of grooves engage the patient and facilitate the advancement of
the paddle lead towards a target implant site by inhibiting the paddle
lead from veering away from the target implant site.

15. The paddle lead of claim 14, wherein at least one of the plurality of
grooves is an arcuate groove.

16. An electrical stimulation system for implantation in a patient,
comprising:a pulse generator for generating electrical pulses;a paddle
lead electrically connectable to the pulse generator, the paddle lead
including a body having a first side and a second side and a first edge
and a second edge;the first side of the body including at least a first
row of at least three electrodes, a second row of at least three
electrodes and a third row of at least three electrodes;each of the
first, second and third row of electrodes being generally parallel and
extending from the first edge of the body to the second edge of the body,
with the second row being positioned intermediate the first and third
rows;the second row of electrodes operable to provide anode guarding for
at least one of the first and third rows of electrodes; andthe second
side of the body including a plurality of grooves, such that when the
paddle lead is being implanted in the patient, the plurality of grooves
engage a portion of the patient and facilitate the advancement of the
paddle lead towards a target implant site by inhibiting the paddle lead
from veering away from the target implant site.

17. The electrical stimulation system of claim 16 wherein when the paddle
lead has been implanted in the patient, at least a portion of the
plurality of grooves engage a portion of the patient and inhibit the
movement of the paddle lead with respect to the position of the paddle
lead in the patient.

18. The electrical stimulation system of claim 17 wherein at least one of
the plurality of grooves is arcuate in shape.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application is a continuation of U.S. application Ser. No.
11/279,712, filed Apr. 13, 2006, pending, which claims the benefit of
U.S. Provisional Application No. 60/671,977, filed Apr. 14, 2005, which
is incorporated herein by reference.

TECHNICAL FIELD

[0002]The present application is generally related to electrical
stimulation for medical purposes and, in particular, to an electrical
stimulation lead, system, and method.

BACKGROUND

[0003]Electrical energy may be applied to a person's spinal cord to treat
a variety of clinical conditions, such as chronic pain. For example,
electrical energy may be applied to the spinal cord to cause a subjective
sensation of numbness or tingling in an affected region of the body,
known as "paresthesia." The electrical energy is delivered through
stimulating electrodes positioned proximate the spinal cord tissue
targeted for stimulation. The stimulation electrodes may be carried by
either two primary vehicles: a percutaneous lead or a laminotomy,
surgical, or "paddle" lead. Percutaneous leads are positioned using a
needle that is passed through the skin and into the epidural space
adjacent the spinal cord such that the stimulating electrodes are
proximate nerve tissue targeted for stimulation. Percutaneous leads
deliver energy generally radially in all directions because of the
circumferential nature of the stimulation electrodes. Paddle leads have a
paddle-like configuration and typically have a number of directional
stimulation electrodes arranged in one or more columns. Paddle leads may
provide more focused energy delivery than percutaneous leads because the
directional stimulating electrodes may be present on only one surface of
the lead. Paddle leads may be desirable in certain situations because
they may provide more direct stimulation to targeted nerve tissue and may
require less energy to produce a desired effect. Directional stimulating
electrodes of paddle leads may be arranged to provide anode guarding or
blocking to more specifically direct stimulation to targeted nerve
tissue.

SUMMARY

[0004]The electrical stimulation lead, system, and method of some
embodiments of the invention may reduce or eliminate certain problems and
disadvantages associated with prior techniques for electrically
stimulating spinal cord tissue.

[0005]According to one aspect, an electrical stimulation portion adapted
for implantation in a person's body to provide therapeutic electrical
stimulation of target spinal cord tissue includes a plurality of
stimulating electrode contacts that are integrated on a first face of the
stimulation portion and are adapted for implantation in the person's body
with the stimulating portion. The plurality of stimulation electrode
contacts are operable to provide electrical stimulation to target spinal
cord tissue. The plurality of stimulation electrode contacts comprise at
least one stimulating electrode contact having a first contact area and
at least one traverse array of stimulating electrode contacts. Each
traverse array comprises a plurality of stimulating electrode contacts
aligned in a row and spaced apart from each other in a direction
approximately perpendicular to a longitudinal axis of the stimulation
portion. Each of the stimulating electrode contacts of the at least one
traverse array have a second contact area no greater than three-fourths
of the first contact area. The stimulation portion includes one or more
terminals each coupled to one or more respective stimulating electrode
contacts of the plurality of stimulating electrode contacts and adapted
to transmit electric current to its one or more respective stimulating
electrode contacts.

[0006]Particular embodiments may provide one or more advantages. For
example, some embodiments provide an electrical stimulating portion
having a transverse array of stimulating electrode contacts that are
aligned in a row in a direction perpendicular to a longitudinal axis of
the stimulation portion and that are smaller than other stimulating
electrode contacts of the lead to increase the ability of the stimulating
portion to flex or bend transversely about the longitudinal axis of the
stimulation portion. In addition, some embodiments include a plurality of
grooves on an opposite face of the stimulating portion that provide
further flexibility. The increased ability of the stimulating portion to
flex or bend transversely about a longitudinal axis of the stimulating
portion enables an operator of the stimulating portion to more easily
implant and position the stimulating portion without damaging the lead or
spinal cord tissue. This also increases comfort to the patient during
use.

[0007]In one embodiment, a paddle lead comprises: a plurality of
stimulating electrode contacts disposed on a first side of a stimulation
paddle of the stimulation lead, the plurality of stimulation electrode
contacts being adapted to allow the stimulation paddle to flex
transversely about the longitudinal axis; a plurality of conductors for
conducting electrical energy to the plurality of stimulating electrode
contacts; wherein the plurality of stimulation electrode contacts are
arranged in at least first, second, and third rows that are disposed
perpendicular to a longitudinal axis of the stimulation paddle; the first
and third rows respectively having multiple electrode contacts
electrically coupled to different conductors of the plurality of
conductors to enable the multiple electrode contacts of the first and
third rows to function in independent cathode states, anode states, or
high-impedance states; the second row being disposed between the first
and third rows, the second row having multiple electrode contacts each
electrically coupled to a common conductor of the plurality of conductors
to cause the multiple electrode contacts of the second row to function in
a common cathode state, anode state, or high-impedance state.

[0008]The foregoing has outlined rather broadly certain features and/or
technical advantages in order that the detailed description that follows
may be better understood. Additional features and/or advantages will be
described hereinafter. It should be appreciated by those skilled in the
art that the conception and specific embodiment disclosed may be readily
utilized as a basis for modifying or designing other structures for
carrying out the same purposes. It should also be realized by those
skilled in the art that such equivalent constructions do not depart from
the spirit and scope of the appended claims. The novel features, both as
to organization and method of operation, together with further objects
and advantages will be better understood from the following description
when considered in connection with the accompanying figures. It is to be
expressly understood, however, that each of the figures is provided for
the purpose of illustration and description only and is not intended as a
definition of the limits of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]For a more complete understanding of some embodiments of the
invention and advantages thereof, reference is now made to the following
description taken in conjunction with the accompanying drawings.

[0011]FIGS. 2A-2C illustrate an example stimulation lead that may be used
to electrically stimulate a person's spinal cord tissue to treat one or
more clinical conditions.

[0012]FIG. 3 illustrates a stimulating portion that may be used to
electrically stimulate a person's spinal cord tissue to treat one or more
clinical conditions showing example electrode contact wiring connections.

[0013]FIG. 4 illustrates an example method of implanting the stimulation
systems of FIGS. 1A and 1B into a person's body with a stimulation lead
located proximate spinal cord tissue for electrical stimulation to treat
one or more clinical conditions.

[0015]According to one representative embodiment, a neurological
stimulation system 10 is used to electrically stimulate target tissue in
a person's spinal cord to treat one or more clinical conditions, such as
chronic pain. In general, an electrical stimulation lead with stimulation
electrodes that include stimulating electrode contacts is implanted
subcutaneously such that the stimulation electrode contacts are located
proximate the target spinal cord tissue. As used herein, the term
"proximate" means on, in, adjacent, or near. Thus, the stimulation
electrode contacts of a stimulation lead are adapted to be positioned on,
in adjacent, or near the target spinal cord tissue. In general, the
stimulation electrode contacts proximate the spinal cord tissue deliver
electrical stimulation pulses to the tissue, which thereby permanently or
temporarily eliminates, reduces, or otherwise treats the one or more
clinical conditions. This may in turn significantly increase the person's
quality of life.

[0016]FIGS. 1A-1B illustrate example neurological systems 10 for
electrically stimulating target spinal cord tissue to treat one or more
clinical conditions, such as chronic pain. In general terms, stimulation
system 10 includes a stimulation pulse generating portion (for example,
implantable electrical stimulation source 12) and one or more implantable
stimulation pulses to the target spinal cord tissue. In operation, both
of these primary components are implanted in the person's body. In
certain embodiments, stimulating source 12 is coupled directly to a
connecting portion 16 of stimulation lead 14. In certain other
embodiments, stimulating source 12 is not coupled directly to stimulating
lead 14. For example, in a microstimulator, a stimulation source 12
instead is integrated and communicates with a stimulating portion, that
may incorporate, one or more electrodes to the stimulating portion. One
example in the art of such a microstimulator is the Bion®
microstimulator manufactured by Advanced Bionics Corporation, while other
microstimulators are known. Whether stimulation source 12 is coupled
directly or indirectly to stimulation lead 14, stimulation source 12
controls the stimulation pulses transmitted to one or more stimulation
electrodes 18 located on a stimulation portion 20 of stimulation lead 14,
positioned proximate the target spinal cord tissue, according to suitable
stimulation parameters (e.g., duration, amplitude or intensity,
frequency, pulse width, etc.). A doctor, the patient, or another user of
stimulation source 12 may directly or indirectly input stimulation
parameters to specify or modify the nature of the stimulation provided to
the patient.

[0017]In one embodiment, as shown in FIG. 1A, stimulation source 12
includes an implantable pulse generator (IPG). An example IPG may be
incorporated in the Genesis® system or the Eon® system
manufactured by Advanced Neuromodulation Systems, Inc. In another
embodiment, as shown in FIG. 1B, stimulation source 12 includes an
implantable wireless receiver. An example wireless receiver may be one
incorporated in the Renew® system manufactured by Advanced
Neuromodulation Systems. The wireless signals are represented in FIG. 1B
by wireless link symbol 24. A doctor, the patient, or another user of
stimulation source 12 may use a controller 26 located external to the
person's body to provide control signals to wireless transmitter 22,
wireless transmitter 22 transmits the control signals and power to the
wireless receiver of stimulation source 12, and stimulation source 12
uses the control signals to vary the stimulation parameters of
stimulation pulses transmitted through stimulation lead 14 to the target
spinal cord tissue. An example of wireless transmitter 22 may be one
incorporated in the Renew® system manufactured by Advanced
Neuromodulation Systems.

[0018]Although specific stimulation systems have be provided as examples,
any appropriate circuitry can be employed to generate suitable
stimulation pulses for electrically stimulating the target spinal cord
tissue using leads 14 according to some representative embodiments.
Example of suitable circuitry for generating stimulation pulses is
described in U.S. Pat. No. 6,609,031, which is hereby incorporated by
reference as if fully illustrated and described herein.

[0019]FIG. 2A illustrates an example stimulation lead 14 that may be used
for electrically stimulating nerve tissue in a person's spinal cord to
treat one or more clinical conditions, such as chronic pain. As described
above, stimulation lead 14 includes stimulation electrodes 18. Each
stimulation electrode 18 includes one or more stimulation electrode
contacts adapted to be positioned proximate target spinal cord tissue and
used to deliver to the target spinal cord tissue stimulation pulses
received from stimulation source 12. Stimulation lead 14 may be referred
to as a laminotomy, surgical, or paddle stimulation lead. The electrode
contacts forming electrodes 18 are spaced apart from one another along
one surface of stimulation portion 20. In particular embodiments,
electrode contacts are separated from each other by one or more
insulative materials. An insulative material of a stimulation lead may
comprise an insulating, dielectric, or other material having a lower
conductivity that a metal or other material used for form the stimulation
electrode contacts of stimulation lead 14.

[0020]Stimulation lead 14 also includes one or more terminals 20 coupled
to stimulation source 12 (illustrated in FIGS. 1A and 1B). Each terminal
20 is also coupled to one or more electrode contacts using electrical
conductors running through stimulation lead 14 to transmit stimulation
pulses to the electrode contacts. As discussed below, in the illustrated
embodiment, electrodes 18d and 18f each comprise three electrode contacts
spaced apart from each other and separated by one or more insulative
materials. In this case, one terminal 20 may be coupled to each of the
three electrode contacts operatively set to function as one electrode 18d
and 18f. For example, terminal 20d may be coupled to the three electrode
contacts forming stimulation electrode 18d and terminal 20f may be
coupled to the three electrode contacts forming stimulation electrode
18f. The selection of the particular electrode contacts forming
particular electrodes 18 to which particular terminals 20 are coupled may
be made in any suitable manner to satisfy the objectives in particular
embodiments. As illustrated, the electrode contacts of stimulation lead
14 are set to function as eight separate electrodes (18a-18h). In some
embodiments, each electrode contact of a stimulation lead may be set to
operate as a separate electrode. For example, with respect to stimulating
portion 20, each of the three electrode contacts of electrode 18d and
each of the three electrode contacts of electrode 18f could be set to
operate as separate electrodes. Thus, those six electrode contacts could
operate as six separate electrodes. If each electrode contact of
stimulation lead 14 were set to operate as a separate electrode (with
corresponding changes in wiring and the number of terminals 20), then the
illustrated stimulation lead 14 would have twelve separate electrodes.

[0021]Electrode contacts forming electrodes 18 emit electrical stimulation
energy received from stimulation source 12 in a direction generally
perpendicular to the surface of stimulation lead 14 on which they are
located. In operation, at any particular time, each electrode 18 may be
programmed, configured, or otherwise set as an anode (+), as a cathode
(-), or in an "off" state. An electrical current "flows" from an anode to
a cathode. Consequently, a range of simple to complex electrical fields
can be created by setting electrode contacts in various combinations of
anodes, cathodes, and "off" states.

[0022]In the illustrated embodiment, electrodes 18d and 18f each comprise
a traverse array of three electrode contacts aligned in a row in a
direction approximately perpendicular to longitudinal axis 19 of
stimulation lead 14. Thus, stimulation electrode 18d comprises three
separate electrode contacts connected to operate as one electrode, and
stimulation electrode 18f comprises three separate electrode contacts
connected to operate as one electrode. In the illustrated embodiment, the
electrode contacts of the stimulation lead generally have an oblong
shape. In addition, each electrode contact of electrodes 18d and 18f are
approximately three-fourths the size (e.g., as measured by the surface
area of the electrode contact) of the oblong electrode contacts forming
electrodes 18a, 18b, and 18c, 18e, 18g, and 18h. Particular embodiments
may include a stimulation lead with electrode contacts having any
suitable shapes and sizes, which may be uniform or different, according
to particular needs. Some embodiments may include a stimulation lead 14
having electrode contacts that are at least two to four times the size of
other electrode contacts of the stimulation lead 14.

[0023]In certain embodiments, the use of multiple separate electrode
contacts to act as a single electrode 18 and arranged across stimulation
lead 14 enhances the ability of stimulation lead 14 to bend or flex, such
as transversely across longitudinal axis 19 of stimulation lead 14. If
electrode 18d, for example, comprised a single electrode contact arranged
across the paddle-shaped stimulating portion in a perpendicular
relationship to electrodes 18a, 18b, 18c, 18e, 18g, and 18h, then
stimulation lead 14 would be less able to bend or flex transversely about
longitudinal axis 19. In addition, the separate electrode contacts of
electrodes 18d and 18f in the illustrated embodiment are aligned in rows
across stimulation portion 20 to further enhance the ability of
stimulation lead 14 to bend or flex transversely about longitudinal axis
19. Particular embodiments may include electrode contacts arranged in any
suitable manner to provide increased flexibility of stimulation lead 14
as appropriate or desired.

[0024]In certain embodiments, electrodes 18 may be set and arranged as
appropriate to provide anode guarding or blocking. As indicated above,
current flows from an anode to a cathode. An anode guard functions, in
part, to laterally limit an applied electrical field to assist in
reducing extraneous stimulation of spinal cord and other tissue
surrounding the target spinal cord tissue. In certain embodiments, since
a cathode electrode 18 provides the actual stimulation of the target
spinal cord tissue (i.e., stimulation occurs at or neat the cathode), one
or more anode electrodes 18 may be positioned around or otherwise
relative to one or more cathode electrodes 18 to focus an applied
electrical field in the vicinity of the one or more cathode electrodes
18. Thus, electrodes 18 set and arranged to provide anode guarding or
blocking may enable stimulation lead 14 to apply more focused and
therapeutically effective stimulation energy than applied if electrodes
were otherwise set or arranged. Setting electrodes 18 to provide anode
guarding or blocking may comprise setting individual electrodes 18 as
cathodes or anodes in a manner sufficient to provide such functionality,
and arranging electrodes 18 to provide anode guarding or blocking may
comprise positioning electrodes 18 on stimulation lead 14 in a manner
sufficient to provide such functionality.

[0025]As indicated above, in particular embodiments, separate electrode
contacts may be programmed to function as separate electrodes. In
addition, any number of separate electrode contacts may be combined to
operate as a single electrode in any suitable manner (e.g., as the three
separate electrode contacts of electrode 18f are adapted to operate as a
single electrode). The ability to, as is desired, to program separate
electrode contacts to operate as one or more electrodes, whether set as
cathodes, anodes, or in high impedance, open circuit or "off state,"
provides great flexibility in stimulating options, particular with
respect to anode guarding or blocking functionality.

[0026]FIG. 2B is an illustration of stimulation lead 14 that shows the
underside of stimulation portion 20, or the opposite side of stimulation
portion 20 from that shown in FIG. 2A. Stimulating portion 20 includes
grooves 21 running the length L of stimulation portion 20. Grooves 21
reduce the area of the underside of stimulating portion 20 contacting
tissue. In certain embodiments, grooves 21 aid in stabilizing stimulation
lead 14 laterally when stimulation lead is being implanted proximate
target spinal cord tissue and thereafter. For example, grooves 21 may
help prevent stimulation lead 14 from veering to one side or the other as
stimulation lead 14 is advanced along the dorsal column midline during
implantation and may further help prevent stimulation lead 14 from
slipping to one side of the dorsal column midline stimulation lead 14 has
been implanted and thereafter. In certain embodiments, grooves 21 also
further enable stimulation lead 14 to bend or flex transversely about
longitudinal axis 19. While five grooves 12 are shown, particular
embodiments may include any number of grooves 21 arranged in any suitable
manner. Preferably, multiple grooves 21 are transversely positioned
coincident with the portions of the paddle face that do not include
electrical contacts, thereby facilitating the flexing characteristics of
lead 14. In an alternative embodiment, grooves 21 can be filled or
replaced with longitudinal segments of a polymer material having a
reduced durometer relative to insulative material of the remaining
portion of the paddle. The selection of the durometer for the
longitudinal segments of material can be made to facilitate transverse
flexing of the paddle.

[0027]FIG. 2C is a cross-sectional view of stimulating portion 20 taken
along line 2C-2C of FIG. 2B. As illustrated, grooves 21 are formed as
round cut-outs of stimulation portion 20. However, other embodiments may
include grooves 21 having other suitable shapes or configurations.

[0028]FIG. 3 illustrates a stimulating portion 50 that may be used to
electrically stimulate a person's spinal cord tissue to treat one or more
clinical conditions showing example electrode contact wiring connections.
Stimulation portion 50 may be similar to stimulating portion 20 described
above in regard to FIGS. 1A, 1B, 2A, 2B and 2C. Stimulation source 50
includes stimulation electrode contacts 60-71 having varying shapes and
sizes. In the illustrated embodiment, electrode contacts 60-62 and 66-68
are generally round and each have a size approximately three-fourths the
size of each oblong electrode contact 63-65 and 69-71.

[0029]The illustrated embodiment includes electrical conductors 80a-80h
coupled to electrode contacts 60-71. Electrical conductors 80a-80h may be
coupled to terminals coupled to a stimulation source, such as terminals
20a-20h, respectively of FIGS. 2A and 2B. Electrical conductors 80a-80h
transmit stimulation pulses from a stimulation source to electrode
contacts 60-71. The actual connections of electrical conductors to
electrode contacts may implemented in any suitable manner, such as
physically connecting electrode conductors to portions of electrode
contacts on the underside of such contacts exposed through the underside
of stimulation face of stimulation portion 50.

[0031]In addition, stimulation portion includes conductors 82a-82b and
84a-84b. Electrical conductor 82a couples electrode contact 66 with
electrode contact 67 and electrical conductor 82b couples electrode
contact 67 with electrode contact 68. Thus, since electrode contacts
66-68 are each coupled together (e.g., through electrical conductors 80d,
82a, and 82b), they may be operatively set to function as one electrode.
In addition, electrical conductor 84a couples electrode contact 61 with
electrode contact 62 and electrical conductor 84b couples electrode
contact 60 with electrode contact 61. Thus, since electrode contacts
60-62 are each coupled to together (e.g., through electrical conductors
80f, 84a, and 84b), they may be operatively set to function as one
electrode.

[0032]Thus, the wiring of the illustrated embodiment is such that
stimulation portion 50 includes electrode contacts that may function as
eight separate electrodes. Electrode contacts 63-65 and 69-71 may
function as six separate electrodes. Electrode contacts 63-65 and 69-71
may function as a single electrode and electrode contacts 66-68 may
function as a single electrode. As indicated above, stimulating portions
of other embodiments may include electrode contacts wired to function as
any number or type of electrodes.

[0033]FIG. 5 depicts an alternative paddle design according to one
representative embodiment. As shown in FIG. 5, paddle lead 500 comprises
electrode contacts 18a, 18b, 18c, 18e, 18h, and 18g implemented in
substantially the same manner as the electrode contacts of stimulation
portion 20 shown in FIG. 2A. Each of these electrode contacts are
preferably separately coupled to different conductors of the lead to
allow these contacts to independently function in cathode, anode, or high
impedance states. Preferably, grooves 21 (previously shown in FIG. 2B)
are disposed on the other side of paddle lead 500 to facilitate the
flexibility of the paddle structure of lead 500.

[0034]The electrode contact design of paddle lead 500 differs from the
design shown in FIG. 2A with regard to the electrode contacts intended to
perform anodal blocking. Specifically, electrodes 510a and 510b are
respectively formed of three separate bar-shaped electrode contacts. The
separate electrode contacts occupy more surface area than the
corresponding electrode contacts of stimulation portion 20. However, the
separate electrode contacts are spaced apart by sufficient space to
enable the paddle structure to transversely flex at locations 501 and
502. To electrically couple each of the separate electrode contacts
together, a trace or strip of flexible conductive epoxy 510 is placed
between the separate electrode contacts. Additionally, the trace or strip
of epoxy material 510 is oriented in a transverse direction on the paddle
structure to facilitate the flexibility of the paddle at locations 501
and 502. The traces or strips 510 of conductive epoxy can be overlaid
with suitable bio-compatible, bio-stable polymer depending upon the
characteristics of the selected epoxy material.

[0035]A thin film conductor can be utilized for traces or strips 510
according to an alternative embodiment. The thin film conductor traces
can be formed in multiple layers. For example, a first thin metal layer
can be formed on the polymer substrate of the paddle structure using
titanium, chromium, aluminum or nickel. To enhance adherence of this
coating to the polymer material, the coating is either concurrently
bombarded during its deposition by high energy ions, which serve to
"shot-peen" the film layer into the surface of the polymer and to
continuously break up the coating from an amorphous/columnar structure to
a nanocrystalline structure, exhibiting over-lapping platelet regions.
The concurrent bombardment is commonly referred to by the acronym "IBAD"
for ion beam assisted deposition. Alternatively, so-called ion beam
enhanced deposition or IBED may be used where ion beam bombardment is
applied subsequent to the deposition of the metallic layer.

[0036]A second thin metal film layer or coating is subsequently deposited
over the first layer using palladium or platinum to function as a
self-alloying/oxygen diffusion barrier layer. The deposition preferably
takes place in the presence of high energy ions to enhance stitching
between the base layer and the second layer to provide a desired
stress-free and non-columnar structure. A third metal film layer is then
applied to a predetermined thickness to function as a bulk conductive
layer. The third metal layer preferably comprises platinum or silver or
another similar conductive element or alloy. A final bio-compatible,
bio-stable conductive layer is applied for exposure to the tissue of the
patient. By minimizing the thickness of the conductive traces and by
orienting the traces transversely on the paddle, paddle lead 600 is able
to flex about locations 501 and 502.

[0037]FIG. 6 depicts paddle lead 600 according to another representative
embodiment. Paddle lead 600 is preferably implemented in a manner that is
substantially similar to paddle lead 500 except paddle lead 600 includes
multiple rows 601, 602, and 602 of independent electrode contacts (in
this embodiment, there are five independent electrode contacts per row).
FIG. 7 depicts paddle lead 700 that is substantially the same as paddle
lead 600 except that paddle lead 700 comprises longitudinal electrode
contacts 701 on the edges of the paddle structure to perform lateral
anode blocking as appropriate for a given therapeutic application. The
multiple rows 601, 602, and 603 of paddle leads 600 and 700 are
advantageous in that the various rows can be used substantially
independently to address complex pain patterns in a substantially
simultaneous manner. For example, row 601 could be utilized to treat
chronic pain in a first limb and row 603 could be utilized to treat
chronic pain in a second limb. Anodal blocking may occur between the two
rows 601 and 603 to substantially cause the electrical fields associated
with those rows to be independent from each other. Additionally, the
greater number of electrodes in a given row enables greater freedom in
steering an applied electrical field in the transverse direction as
necessary for a particular patient and pain condition.

[0038]FIG. 4 illustrates an example method of implanting stimulating
system 10 of FIGS. 1A-1B into a person's body with stimulation lead 14
located proximate target spinal cord tissue for electrical stimulation to
treat one or more clinical conditions, such as chronic pain. At step 30,
stimulation lead 14 is implanted such that one or more electrodes 18 of
stimulation lead 14 are positioned proximate target spinal cord tissue.
Techniques for implanting stimulation leads such as stimulation lead 14
are known to those skilled in the art. At step 32, stimulation source 12
may be coupled directly to connecting portion 16 of stimulation lead 14.
Alternatively, as described above, stimulation source 12 may not be
coupled directly to stimulation lead 14 and may instead be coupled to
stimulation lead 14 via a wireless link.

[0039]Intra-implantation trial stimulation may be conducted at steps
34-38. Alternatively, the method may proceed from step 32 to 40. At step
34, stimulation source 12 is activated to generate and transmit
stimulation pulses to the target spinal cord tissue via one or more
electrodes 18 of stimulation lead 14 positioned proximate the target
spinal cord tissue. At step 36, subjective or objective testing and
analysis may be performed to determine whether one or more clinical
conditions are sufficiently improved, one or more stimulation patterns
may be adjusted, stimulation lead 14 may be moved incrementally or even
re-implanted, or both of these modifications may be made at step 38 and
the trial stimulation and analysis repeated until the one or more
clinical conditions are sufficiently improved. Once the stimulation
parameters have been properly set and stimulation lead 14 has been
properly positioned such that the one or more clinical conditions are
sufficiently improved, intra-implantation trial stimulation is complete.

[0040]Once stimulation lead 14 has been properly implanted and secured,
and any trial stimulation completed, stimulation source 12 is implanted
as step 40. Techniques for implanting stimulation source 12 are known to
those skilled in the art. The implant site is typically a subcutaneous
pocket formed to receive and house stimulation source 12. The implant
site is usually located some distance away from the insertion site, such
as in or near the upper chest or buttocks. Where stimulation lead 14
includes connecting portion 16, connecting portion 16 is tunneled, at
least in part, subcutaneously to the implant site of stimulation source
12 at step 42. At step 44, a doctor, the patient, or another user of
stimulation source 12 may directly or indirectly input stimulation
parameters for controlling the nature of the electrical stimulation
provided to the target spinal cord tissue, if not already set during any
intra-implantation trial stimulation period. When appropriate,
post-implantation trail stimulation may be conducted, over one or more
weeks or months for example, and any necessary modifications made
accordingly.

[0041]Although representative embodiments and advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing from
the spirit and scope of the appended claims. Moreover, the scope of the
present application is not intended to be limited to the particular
embodiments of the process, machine, manufacture, composition of matter,
means, methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from this disclosure,
processes, machines, manufacture, compositions of matter, means, methods,
or steps, presently existing or later to be developed that perform
substantially the same function or achieve substantially the same result
as the corresponding embodiments described herein may be utilized without
departing from the scope of the appended claims. Accordingly, the
appended claims are intended to include within their scope such
processes, machines, manufacture, compositions of matter, means, methods,
or steps.